How paradoxical are the effects of thought suppression ? : the nature of mental control and the factors that influence it

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Author

Erskine, James Anthony Keith

Attention

2299/14187

Abstract

This thesis attempted to expand knowledge of intentional thought control in several
directions. The primary aim was to provide an account of intentional thought suppression
by relating the phenomenon to the methods used to assess the rebound effect, internal
personality factors and psychopathology. An additional aim was to examine the rebound
effect from the broader perspective of relating thought suppression to aging, the
perception of volitional control and memory for future intentions.
The results indicate that the method used to index the rebound effect may have a large
impact on whether the effect is found or not. The rebound effect was obtained with the
original method of assessment (Wegner, 1987) but not with the modified method that is
currently used in the research. More importantly, the rebound effect was affected by the
personality variable of state vs. action orientation (Kuhl & Beckmann, 1994b). State
oriented participants demonstrated the rebound effect, whereas action oriented
participants did not, irrespective of the method used to assess the effect. This finding
provides support for the new intentional account of the rebound effect proposed in the
thesis that is based on the Intention Superiority Effect (Kuhl, 1994) and the theory of
action control (Kuhl & Beckmann, 1994b). The results also showed that suppression and
expression performance in the laboratory did not have a common underlying mechanism.
Successful expression performance was related to poorer suppression performance and
visa versa.
The results of the thesis also question the validity of the White Bear Suppression
Inventory (Wegner and Zanakos, 1994)a s a measure of the tendency to suppress thoughts
in everyday life. In young adults, apart from thought suppression, it also appears to
measure the tendency to experience thought intrusions (rumination). Moreover, there was
no relationship between the use of thought suppression in everyday life and actual
suppression performance in the laboratory.A different pattern of results were obtained in
a group of older adults (over 65 years). In addition, older adults reported using thought
suppression reliably less frequently than young adults (i. e. had lower WBSI scores), and
displayed much higher levels of repressive coping style than young people, 37% (old) vs.
9.5% (young).
Finally, the results showed that thought suppression can also have other ironic effects on
behaviour and perception. Participants attempting to complete an action while
suppressing thoughts of the intention to perform this action came to feel as if the act was
less intentionally performed. In contrast, participants completing actions under thought
expression instructions rated the actions as more intentional. Furthermore, suppressing or
expressing thoughts of an upcoming intention did not help one to remember to enact the
intention with an enhanced frequency relative to thinking about a completely unrelated
intention.
Taken together, the findings have important implications for research on thought
suppression and mental control by showing that the rebound effect is less robust than
suggested by previous research. Thus, some of the controversy surrounding the rebound
effect can be explained on the basis of individual differences in personality type (state vs.
action orientation) as well as the methods used to index the effect. The results also raise
several important questions for future research in this area (e. g. the validity of WBSI,
effects of age on thought suppression and repression).